Black screen 60+ mins to boot

Toshiba satellite - running windows 10 - ran fine booted quickly for several months after install of windows 10. Last few weeks when powering on - black screen for 60+ minutes and then the logon screen appears asking for password and notebook runs fine. ran disk check - and no issues, anti virus up to date, -
since I can't stare at screen for 60+ minutes no idea what appears on screen prior to prompt for password - glance over at pc from time to time and eventually see logon screen. Tired safe boot and same thing. sometimes if PC doesn't boot within 60-90 minutes I have to hit power button to kill power and then attempt power on again - and wait.
OS Name Microsoft Windows 10 Home